The present invention relates to cigarettes and other smoking articles such as cigars, pipes and the like. In particular, the invention relates to processes for extracting flavor substances from tobacco; and to smoking articles made, at least in part, with extracted tobacco flavor substances.
Cigarettes, cigars and pipes are the most popular forms of tobacco smoking articles. Many smoking products and improved smoking articles have been proposed through the years as improvements upon, or as alternatives to, these popular forms of tobacco smoking articles. Examples of improved smoking articles are the cigarettes and pipes described in U.S. Pat. Nos. 4,756,318; 4,714,082 and 4,708,151, which generally comprise a fuel element, a physically separate aerosol generating means, and a separate mouthend piece.
Tobacco substitute smoking materials have likewise been proposed as improvements upon and/or as alternatives to tobacco. See, e.g., U.S. Pat. No. 4,079,742 to Rainer et al.
Generally, natural tobacco flavors are important for the taste, aroma and acceptance of smoking products, including substitute smoking materials. Thus, the search for natural tobacco flavor additives (or flavor substances) is a continuing task.
For instance, U.S. Pat. No. 3,424,171 describes a process for the production of a non-tobacco smokable product having a tobacco taste. Tobacco is subjected to a moderate (i.e., below scorching) heat treatment, i e., at from about 175.degree. to 200.degree. C. (or about 350.degree.-400.degree. F.), to drive off aromatic components. These components are trapped on adsorbent charcoal, and removed from the charcoal by solvent extraction. The smokable product disclosed is vegetable matter, treated with the mixture of tobacco aromatic components and the solvent.
Similarly, U.S. Pat. No. 4,150,677 describes a process for the treatment of tobacco which comprises the steps of: (1) contacting tobacco which contains relatively high quantities of desirable flavorants with a stream of non-reactive gas, under conditions whereby the tobacco is heated in a temperature range from about 140.degree. to about 180.degree. C.; (2) condensing the volatile constituents of the resulting gaseous stream; and (3) collecting said condensate. The condensate may be used subsequently to flavor a smoking material in order to enhance the organoleptic properties of its smoke.
British Patent No. 1,383,029 describes a method for obtaining tobacco aroma substances which comprises an extraction treatment wherein the components of the tobacco that are soluble in a suitable solvent are extracted and the residue obtained after removing the solvent is subjected to heat treatment at a temperature from 30.degree. to 260.degree. C.
Similarly, U.S. Pat. No. 3,316,919 describes a process for improving the taste of smoking tobacco that entails adding a powder of freeze dried aqueous tobacco extract to tobacco cut filler in amounts ranging from about 5 to 10% by weight.
U.S. Pat. Nos. 5,038,802 to White et al. and 5,016,654 to Bernasek et al. disclose extraction processes which heat tobacco and then pass an inert atmosphere through the heating chamber to collect volatiles from the tobacco. The volatiles are then fractionated in downstream operations, which include liquid sorbents, cold temperature traps and filters.
While these processes have produced flavor substances acceptable for use in many smoking articles, they have either not been suitable for some smoking articles, such as those that use a heat source that generates a low temperature in the substrate to which they are applied, or they have not been applied to such substrates in a fashion that permits an optimum release therefrom. Thus, it would be desirable to provide processes for producing better flavor substances from tobacco and smoking articles which utilize extracted tobacco flavors in a manner so as to obtain an optimum release of the flavor substances from the smoking article.